Terminals may be generally classified as mobile/portable terminals or stationary terminals according to their mobility. Mobile terminals may also be classified as handheld terminals or vehicle mounted terminals according to whether or not a user may directly carry the terminal.
Mobile terminals have become increasingly more functional. Examples of such functions include data and voice communications, capturing images and video via a camera, recording audio, playing music files via a speaker system, and displaying images and video on a display. Some mobile terminals include additional functionality which supports game playing, while other terminals are configured as multimedia players. More recently, mobile terminals have been configured to receive broadcast and multicast signals which permit viewing of content such as videos and television programs.
Users mostly hold and use the mobile terminals by their hands and furthermore, the mobile terminals may be expanded to wearable devices which may be worn on their bodies. The wearable devices include a watch-type mobile terminal, a glass-type mobile terminal, a head mounted display (HMD), and so on.
Among others, the watch-type mobile terminal is formed by the adding of electronic, communication and multimedia functions to a watch which a human being always wear, and it seems that a big market is formed in the future because the watch-type mobile terminal does not provide antipathy to the human being.
Thus, research, development and commercialization of the watch-type mobile terminal are being actively conducted.
The watch-type mobile terminal includes a bezel including a user input unit, which is so called “crown key”. However, a conventional watch-type mobile terminal has a difficulty in replacing a bezel coupled to a display unit with new one. In addition, the number of hard keys included in the bezel is fixed so that only fixed functions are performed.